The block is at the machine shop now.
They will perform a crack test to make sure that that is the only crack and then sleeve #8 with a "B" sleeve -which I think is a ~.094" wall.
A "C" sleeve is a nice & thick .125" wall, but that removes too much of the original cylinder.
The plan then is to bring it home and do a "short" grout fill (up to the lower edge of the welch plugs) for better support, return to the shop for honing, then back home for reassembly.

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The block is at the machine shop now.
They will perform a crack test to make sure that that is the only crack and then sleeve #8 with a "B" sleeve -which I think is a ~.094" wall.
A "C" sleeve is a nice & thick .125" wall, but that removes too much of the original cylinder.
The plan then is to bring it home and do a "short" grout fill (up to the lower edge of the welch plugs) for better support, return to the shop for honing, then back home for reassembly.

It's sink or swim Steve.
Hindsight for me is nothing but an arsehole, but in this particular case the leaking rear main seal was a good thing. It prevented me heading to the track and allowed me to find a couple of things.
The crack however.. Well thank you god!

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I was going to accurately repair two intake threads that were a bit iffy, and thought I'd just Recoil the lot on both heads.
I should have bought a bigger mill. That's at full height.
Just one bloody inch Damn it!
Drill press.

Cranky's linished my crank for free then found the front gear wasn't quite sitting true thanks to the lousy machined radius on the GM crank. the fix is to grind the radius and also ensure that the abutment for the gear is true.
Those marks are from the gear moving on the snout.

Here you can see the gear has been marred slightly too.

levelling the block and preparing to grout the water jacket. The main caps are torqued and the head will also be torqued in place once poured. That is to pull the cylinder into shape while the grout sets.

Basic stuff..

Poured up to the lower edge of the welch plugs. This should not effect running temps based on hearsay! Although, this most likely will result in a slightly warmer oil temp due to the lack of lower block water cooling.

Doing this with some vacuum hose will allow me to continue to use the drain plug. The hose is removed after curing.

Just a couple of pics showing my lovely bronze lifter bushings..

Nice view.

The sleeve was fitted before grouting and here I'm about to re-die-grind the valve notches. Now that the grout has cured, the block can go back for final honing, but still a 2 week wait on new rings.

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The shoulder on the crank for the timing gear was said to have never been final machined. It took removing .008" to have it run true!
The good news is that that removed enough material to clean up the marks from the gear and allowed a nice .125" radius.

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I was able to just gain enough room on the mill to recoil the threads.
I bought this used angle plate to set the head up as the intake holes are tapped in at 15° to the deck.

After traversing with a dial indicator to ensure I have the head level and square on the mill, I used an edge finder to locate the center of the thread.
I still didn't rely on the set up, I checked every thread center individually.

3/8-16 threads require a 29/64" tapping drill, so a 3/8" end mill being .015" less is close enough to cut out the old threads.

Using the mill to align the tap nice and square, I hand tap the repair thread.

New thread inserts that are stronger than the originals, as is the beauty of recoiling. A stronger thread material that "bites" into a larger surface area.
Being stainless steel inserts, make sure you never use stainless steel fasteners. Even with a quality anti-seize, stainless galls on itself badly. Same with aluminium. Never use alum plugs in an alum manifold. Bad news.

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